Transcript Feedback control of the LHW Power by HVPS

Feedback control of the
LHW Power by HVPS
Huang Yiyun
Institute of Plasma Physics, Chinese Academy of
Science,
P.O.Box 1126, Hefei, Anhui, 230031, P.R.China
(2003.9)
Content
1. Background
2. The 2.45GHz 1MW LHCD system and HVPS
3. The purposes of the feedback control
4. Mathematic model of the control system
5. Simulation result and analyse
6. Conclusion
1. Background
a. LHCD---to heat and drive the plasma current efficiently.
b. HVPS---to control the output micro-wave power of the
LHCD (LHW)through regulating high voltage of the HVPS.
c. Traditionally---Voltage of the HVPS is feedback controlled
to hold the power of LHW constant.
d. Expectation ---Power of the LHW is feedback controlled
to dissipate fluctuation of other disturbances.
2. The 2.45GHz 1MW LHCD system and HVPS
a.
The 2.45GHz 1MW LHCD system
high voltage power supply
-35KV/40A
dual cerimic windows
dual power coupler
wave guide
Anode
circulator
magnetic coil
Klystron
3*4 antenna
cathode
magnet PS
LHW power acquisition
Ti pump
filament PS
oscillator
*12
2.45 GHz
sub-PIN
phase control
amplifier
main PIN
Oscillator—PIN—Phase—Amplifier—Klystron—Circulator—cerimic windows
—Antenna —Plasma
b.
The -35KV/2.8MW HVPS
Rectify transformer
CJ1
RL1
Rc
Zz1
Kx1
5mH
Crowbar
2u
6x Klystron
Star point control
Matching transformer
LEM1
U2
LEM3
LEM2
E-Grid—transformer—switch—star-point controller—rectifier —RLC filter
—Crowbar—klystron
3. The purposes of the feedback control
a.
•
•
•
•
Keep the power of the microwave steadily from fluctuate
Fluctuation from the HVPS.
Fluctuation from the low power ratio frequency driver.
Fluctuation from the other device such as magnet
Protection of reflection power for cerimic windows
b. Modulate the power of the microwave based of the HT-7 experiment
Ram up or down the power of the microwave at any time
4. Mathematic model of the control system
• object properties
CV
Hv(s)
_
PID controller
Uo
Ui+
G1(s)
Pi +
_
Po
G2(s)
G3(s)
PID controller
Ur
Pr
Hp(s)
CP
K
G ( s) 
*
h
Ts  1
1

 
R 
L  

s
LCs 2   R C 
s

1



s
R   R 

p 
p


K
1
1
*
*
0.00167 S  1 0.00236 S  1 0.0153S  1
K=4300
Ts=23.6mS
5. Simulation result
a. The feedback controlled LHW when Fluctuation from the HVPS
HV of HVPS sometime fluctuate due to fluctuation of electrical grid
b. The feedback controlled LHW when Fluctuation from the LHCD
HV of HVPS fluctuate sometime due to fluctuation of low power ratio
frequency driver or other device
c. The LHW feedback control when protection of reflection power
HVPS is feedback controlled
LHW is feedback controlled
One klystron of LHCD system will be cut by sub-PINA when reflection
power endanger cerimic windows
d. Confinement of condition
The controller will result in saturation when the power of LHW
decrease more than 50%,such as 3 or 4 klystron is cut by sub-PIN at
the same time.
The rebound of the power of LHW will endanger the klystron, such
as arc inside etc. which will deduce the natural life of the klystron.
d. The modulated LHW feedback controlled by HVPS
The LHW can be controlled by rated value and time stably by regulating
HVPS with compatible PID law For HT-7 experimental require.
The power of LHW ramp up by HVPS control
6. Conclusion
• To keep the steady plasma current on HT-7 and HT-7U, power of
LHW is need to be feedback controlled against all kinds of
disturbances.
• Setup the control system by analyzing objective properties by
Mathematic model.
• Parameter PID must be adjusted through simulation.
• The LHW can be controlled at rated value and time to satisfied the
requires of experiment.
thanks